The major objective of the proposed research is to provide the necessary volume of data on ultrasonic toxicity related to ultrasound irradiation of the reproductive system of the mouse and mouse embryo so that further aid can be provided towards the goal of establishing quantitative values for permissible levels of operation and delivery formats for medical ultrasonic devices. This toxicity information will be provided by establishing quantitative relationships between the ultrasonic parameters and delivery formats (those used in medical practice) and magnitudes of bioeffects which have been detected. These dosage vs. effects curves will be provided for irradiation of gonadal tissues of adult males and females and scoring of effects will be made on these adult animals and their first generation offspring. A multiple generation search for possible mutagenic effects will be made by irradiating both male and female parents whose progeny are in turn irradiated and bred on a selected brother/sister basis. Irradiated males in this study will also be mated with animals having known recessive traits. The irradiation dosage for this study will be lower than that which has indicated any significant level of bio-effects as seen in ongoing first generation studies. A small pilot study will be conducted involving a search for possible chromosonal aberrations in acute experiments (animals survival less than 24 hours).